---

yaml
---
r: 145103
b: refs/heads/master
c: b4ecc12
h: refs/heads/master
i:
  145101: beddd80
  145099: 122c4b2
  145095: 7299dd2
  145087: 9e2be24
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 44408ad7368906c84000e87a99c14a16dbb867fd
+refs/heads/master: b4ecc126991b30fe5f9a59dfacda046aeac124b2

trunk/arch/x86/Kconfig

@@ -498,6 +498,19 @@ config PARAVIRT
 	  over full virtualization.  However, when run without a hypervisor
 	  the kernel is theoretically slower and slightly larger.
 
+config PARAVIRT_SPINLOCKS
+	bool "Paravirtualization layer for spinlocks"
+	depends on PARAVIRT && SMP && EXPERIMENTAL
+	---help---
+	  Paravirtualized spinlocks allow a pvops backend to replace the
+	  spinlock implementation with something virtualization-friendly
+	  (for example, block the virtual CPU rather than spinning).
+
+	  Unfortunately the downside is an up to 5% performance hit on
+	  native kernels, with various workloads.
+
+	  If you are unsure how to answer this question, answer N.
+
 config PARAVIRT_CLOCK
 	bool
 	default n

trunk/arch/x86/include/asm/paravirt.h

@@ -1443,7 +1443,7 @@ u64 _paravirt_ident_64(u64);
 
 #define paravirt_nop	((void *)_paravirt_nop)
 
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) && defined(CONFIG_PARAVIRT_SPINLOCKS)
 
 static inline int __raw_spin_is_locked(struct raw_spinlock *lock)
 {

trunk/arch/x86/include/asm/spinlock.h

@@ -172,7 +172,7 @@ static inline int __ticket_spin_is_contended(raw_spinlock_t *lock)
 	return (((tmp >> TICKET_SHIFT) - tmp) & ((1 << TICKET_SHIFT) - 1)) > 1;
 }
 
-#ifndef CONFIG_PARAVIRT
+#ifndef CONFIG_PARAVIRT_SPINLOCKS
 
 static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
 {
@@ -206,7 +206,7 @@ static __always_inline void __raw_spin_lock_flags(raw_spinlock_t *lock,
 	__raw_spin_lock(lock);
 }
 
-#endif
+#endif	/* CONFIG_PARAVIRT_SPINLOCKS */
 
 static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)
 {

trunk/arch/x86/kernel/Makefile

@@ -89,7 +89,8 @@ obj-$(CONFIG_DEBUG_NX_TEST)	+= test_nx.o
 obj-$(CONFIG_VMI)		+= vmi_32.o vmiclock_32.o
 obj-$(CONFIG_KVM_GUEST)		+= kvm.o
 obj-$(CONFIG_KVM_CLOCK)		+= kvmclock.o
-obj-$(CONFIG_PARAVIRT)		+= paravirt.o paravirt_patch_$(BITS).o paravirt-spinlocks.o
+obj-$(CONFIG_PARAVIRT)		+= paravirt.o paravirt_patch_$(BITS).o
+obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= paravirt-spinlocks.o
 obj-$(CONFIG_PARAVIRT_CLOCK)	+= pvclock.o
 
 obj-$(CONFIG_PCSPKR_PLATFORM)	+= pcspeaker.o

trunk/arch/x86/kernel/paravirt.c

@@ -134,7 +134,9 @@ static void *get_call_destination(u8 type)
 		.pv_irq_ops = pv_irq_ops,
 		.pv_apic_ops = pv_apic_ops,
 		.pv_mmu_ops = pv_mmu_ops,
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
 		.pv_lock_ops = pv_lock_ops,
+#endif
 	};
 	return *((void **)&tmpl + type);
 }

trunk/arch/x86/xen/Makefile

@@ -9,5 +9,6 @@ obj-y		:= enlighten.o setup.o multicalls.o mmu.o irq.o \
 			time.o xen-asm.o xen-asm_$(BITS).o \
 			grant-table.o suspend.o
 
-obj-$(CONFIG_SMP)		+= smp.o spinlock.o
-obj-$(CONFIG_XEN_DEBUG_FS)	+= debugfs.o
+obj-$(CONFIG_SMP)		+= smp.o
+obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o
+obj-$(CONFIG_XEN_DEBUG_FS)	+= debugfs.o

trunk/arch/x86/xen/xen-ops.h

@@ -62,15 +62,26 @@ void xen_setup_vcpu_info_placement(void);
 #ifdef CONFIG_SMP
 void xen_smp_init(void);
 
-void __init xen_init_spinlocks(void);
-__cpuinit void xen_init_lock_cpu(int cpu);
-void xen_uninit_lock_cpu(int cpu);
-
 extern cpumask_var_t xen_cpu_initialized_map;
 #else
 static inline void xen_smp_init(void) {}
 #endif
 
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+void __init xen_init_spinlocks(void);
+__cpuinit void xen_init_lock_cpu(int cpu);
+void xen_uninit_lock_cpu(int cpu);
+#else
+static inline void xen_init_spinlocks(void)
+{
+}
+static inline void xen_init_lock_cpu(int cpu)
+{
+}
+static inline void xen_uninit_lock_cpu(int cpu)
+{
+}
+#endif
 
 /* Declare an asm function, along with symbols needed to make it
    inlineable */